The major goal of the Analytical Microscopy Laboratory is to provide technical expertise in qualitative and quantitative analytical microscopy and to extend these capabilities to all relevant studies in orthopaedics and musculoskeletal research. The Analytical Microscopy Core has four major objectives: 1. To provide morphological techniques and analysis for the study of soft and hard tissues at the light and electron microscopic levels for research programs involving investigators within the biomedical research base at the Hospital for Special Surgery (HSS) and its affiliated institutions; 2. To provide information and training to all investigators regarding the use of techniques in histology, histochemistry, immunocytochemistry and morphometry; 3. To develop further our capacity for systematic and quantitative evaluation of fixed arid living cells analyzed by microscopic techniques (including confocal microscopy);and, 4. To develop new applications of microscopic techniques to fit the research programs of investigators within the Core Center's biomedical research base. This laboratory is unique because the techniques, technical support, and equipment is specifically designed to aid in the study of all musculoskeletal tissues, whether mineralized or not. In addition, the studies can be done at any level of interest from the gross to the subcellular, and because of the working relationships with the other cores, each study can be investigated for change in morphology, chemistry, and mechanics or architec-ture. This environment is very unique and probably does not exist anywhere else in the United States. Because of these strengths, the projects and studies being supported will add significantly to our knowledge of musculoskeletal tissue development and repair.